Conventional fish scaling and cleaning systems have used metal knife blades, such as serrated knives, for scaling fish. However, such systems cannot effectively process frozen fish. The fish must first be thawed to enable the knives to function effectively.
One type of conventional washing apparatus uses water jets to wash fruit, vegetables, or other items. The water is supplied to the jets at pressures typically within the range 250-2000 p.s.i. (i.e., at pressures much less than "super" high pressure). In such conventional washing systems, the water jets are typically oriented substantially perpendicularly to the surface to be washed, to exert normal force (rather than shearing force) on the surface.